1. Field of the Invention
The present invention relates to a storage facility and a storage method using the storage facility. For example, the invention relates to a storage facility and a storage facility involving low-temperature, high-humidity storage of an object to be stored (e.g. agricultural product such as potato, vegetable, fruits, etc.), or precooling of vegetable, and also to a storage method using the system.
2. Description of the Prior Art
As the conventional storage facility and storage method of the above-noted type, there are known the system and method utilizing the direct-cooling refrigerating cycle. For example, there is known a system and method utilizing such direct-cooling refrigerating cycle from e.g. Japanese laid-open patent gazette No. Hei. 5-26557.
Basically, this system is designed to maintain low temperature by absorbing respiration heat of the vegetable stored inside a storage house. Accordingly, for reducing the temperature its inside, this system employs a moisture permeable film (Japanese laid-open patent gazette No. Hei. 6-74646) for maintaining moisture or additionally includes a humidifier (Japanese laid-open patent gazette No. Hei. 8-42960), for forcibly increasing the humidity.
As a small-scale storage, there is known a system referred to icehouse. According to this, in a snowfall region, a hole is dug in the earth, Into this hole, vegetables are introduced, on which snow is put for storage. In recent years, as exemplified by e.g. Japanese patent gazette No. 2598574, there have been attempts in cold districts such as storage facility/storage method in which a heat-exchanger pipe is employed for cooling inside of a storage house in which agricultural products are stored, or storage facility/storage method in which a heat pipe having good cold conducting property during winter time is employed for making artificial frozen soil to be used as cold source (Japanese laid-open patent gazette No. Hei. 7-218080).
Further, regarding precooling, as exemplified by Japanese published patent gazette No. Hei. 7-99991, there is storage facility/storage method in which a product is sealed in a plastic bag to be cooled.
According to the conventional art described above, there is required a significant amount of electricity since a large refrigerator is employed as the ice making machine. Also, in the conventional storage facility too, there is the problem of large consumption of electricity since refrigerating cycle is employed as the heat source. Moreover, in he case of such method using refrigerating cycle, in order to maintain the low temperature inside the storage house of the vegetables, not only the respiration heat is absorbed from the vegetables, but also significant dehydration of the vegetables occurs as the result. Hence, a humidifier or the like needs to be employed, but, this too adds to the electricity consumption.
Further, in order to solve the problem of electricity consumption by the refrigerating cycle, it it conceivable to employ the system called icehouse using snow. However, the density of snow has such small value as 0.27 approximately. Then, in order to adapt it to the system/method, an extremely large amount of snow needs to be prepared and also a large-scale facility too will be necessary for storing the snow. As a result, significant costs will be needed for transportation of snow and building of the facility. Also, in cold districts without snow accumulation, the snow must be transported from a distant place, hence leading to especially high costs.
Therefore, an object of the present invention is to provide a storage facility/storage method solving the above-described problems, not requiring large amount of electricity, suitable of multiple of purposes, allowing storage of storage objects kept under good storage conditions.
According to FIGS. 4-8 and 11, the system comprises a heat-insulating outer shell capable of insulating inner space; an ice storage water tank capable of storing water therein disposed in an ice storage water tank disposing space provided in the inner space of the heat-insulating outer shell; a storage space for storing objects to be stored provided in the inner space of the heat-insulating outer shell; an outside-air inlet opening provided at a lower portion of the heat-insulating outer shell, the inlet opening being capable of introducing outside air into the inner space; an inside-air outlet opening provided at an upper portion of the heat-insulating outer shell, the outlet opening being capable of discharging inside air from the inner space of the heat-insulating outer shell to the outside; and an object entrance-exit opening provided at an upper portion of the heat-insulating outer shell for allowing entrance-exit of the objects to and from the storage space.
According to one feature of the invention defined in claim 1, when the outer air becomes sub-zero condition, the outer air enters through the outside-air inlet opening into the ice storage water tank disposing space, so that the air absorbs latent heat from the water stored in the ice storage water tank for freezing this water. Further, the air contacting the ice storage water tank, by absorbing latent heat from the water, experiences temperature rise, and due to reduction of its density associated therewith, the air is caused to rise in the inner space of the heat-insulating outer shell to be discharged through the inside-air outlet opening to the outside.
Therefore, within the inner space of the heat-insulating outer shell, there is generated upward air current due to the transfer of latent heat associated with freezing of the water, so that the introduction of outside air into the ice storage water tank disposing space and discharge thereof can take place in automatic and continuous manner. Thus, it has become possible to freeze the water inside the ice storage water tank by utilizing the cold source of the cold district which is the natural resource of the earth. Hence, ice can be made inexpensively and energy can be saved, so that the system can contribute significantly to the reduction of carbon dioxide gas output on the earth.
And, by the cold from the ice made in the ice storage water tank disposing space, the storage space can be maintained under refrigerating condition (about 0xc2x0 C.), for allowing storage objects stored in the storage space.
Moreover, since the storage space can be maintained at a high humidity by means of saturated water vapor pressure, storage of objects under low-temperature, high-humidity environment can be realized.
Therefore, it becomes possible to provide an environment suitable for storage of agricultural products (potatoes, vegetables, fruits, live flowers, etc). Furthermore, since the storage space can be maintained at the temperature of 0xc2x0 C. approximately, the system may be used also for freezing storage of frozen articles frozen below zero.
Further, due to the relationship between the temperature and density of the air (i.e. the lower the temperature, the higher the humidity), even if the entrance-exit opening is kept open during the entry or exit of the objects into or from the storage space, in case the outside air temperature is higher than the inside air temperature of the storage space, it is possible to minimize entry of the outside air into the inner space of the heat-insulating outer shell.
Therefore, it becomes possible to minimize the leak of the cool air of the storage space to the outside, so that the temperature of the storage space can be maintained easily.
Next, the above-described freezing of water utilizing latent heat will be described with reference to FIG. 1(a).
The figure records temperature variation relative to time base occurring in water placed in a vat disposed inside a freezer. When the temperature of the freezer becomes below 0xc2x0 C., the temperature of the water in the vat is kept at 0xc2x0 C. approximately. Upon lapse of certain time, however, the water changes into ice and the temperature becomes below 0xc2x0 C. gradually. However, as shown in FIG. 1(b), the temperature of the substance in the vat not radiating latent heat therefrom follows the temperature of the freezer. This experimental fact is demonstrated by FIG. 2. When the outside temperature falls toward point B, the temperature of water becomes 0xc2x0 and some of the water changes into ice and the energy discharged during this process is called latent heat. This latent heat discharges energy of 80 Kcal per 1 kg of water until the point A is reached where the water is frozen completely. With additional cooling after completion of discharge of latent heat, the ice becomes below 0xc2x0 C. This phenomenon is reversible. Conversely, water becomes 0xc2x0 C. by giving its heat to ice. The ice receives the heat, but is maintained at 0xc2x0 C. until it receives 80 Kcal per 1 kg. Such received heat too is called latent heat. The present invention utilizes mainly the condition between the point A and the point B. The large heat capacities of water and ice contributes greatly to the maintenance of 0xc2x0 C. environment, that is the system being less susceptible to the outside temperature.
According to one feature of the present invention as exemplified by the illustrations of FIGS. 5, 7 and 11, the system comprises: a heat-insulating outer shell capable of insulating inner space; an ice storage water tank capable of storing water therein disposed in an ice storage water tank disposing space provided in the inner space of the heat-insulating outer shell; a storage space for storing objects to be stored provided in the inner space of the heat-insulating outer shell; an outside-air inlet opening provided at a lower portion of the heat-insulating outer shell, the inlet opening being capable of introducing outside air into the inner space; and an inside-air outlet opening provided at an upper portion of the heat-insulating outer shell, the outlet opening being capable of discharging inside air from the inner space of the heat-insulating outer shell to the outside, wherein the ice storage water tank disposing space is disposed so as to encompass the storage space.
Another feature of the invention is that it has become possible to freeze the water without using a blower driving unit or freezer inside the ice storage water tank by utilizing the cold source of the cold district which is the natural resource of the earth. Hence, ice can be made inexpensively and energy can be saved, so that the system can contribute significantly to the reduction of carbon dioxide gas output on the earth, and storage of objects under low-temperature, high-humidity environment can be realized.
Moreover, as the ice storage water tank disposing space is interposed between the storage space and the outside, the ice storage water tank disposing space not only provides cold to the storage space, but also guards the storage space, whereby the influence from the environmental change of the outside air to the storage space may be advantageously reduced. Therefore, it becomes possible to maintain the storage of the storage object under more favorable conditions for a longer time.
Accordingly, it becomes possible to provide an environment suitable for storage of agricultural products (potatoes, vegetables, fruits, live flowers, etc). Furthermore, the system may be used also for freezing storage of frozen articles frozen below zero.
According to another feature of the present invention as exemplified by the illustrations of FIGS. 5, 7 and 11, the system comprises: a heat-insulating outer shell capable of insulating inner space; an ice storage water tank capable of storing water therein disposed in an ice storage water tank disposing space provided in the inner space of the heat-insulating outer shell; a storage space for storing objects to be stored provided in the inner space of the heat-insulating outer shell; an outside-air inlet opening provided at a lower portion of the heat-insulating outer shell, the inlet opening being capable of introducing outside air into the inner space; and an inside-air outlet opening provided at an upper portion of the heat-insulating outer shell, the outlet opening being capable of discharging inside air from the inner space of the heat-insulating outer shell to the outside, wherein the heat-insulating outer shell has a cylindrical shape.
According to another feature of the invention it has become possible to freeze the water inside the ice storage water tank without using a blower driving unit or freezer by utilizing the cold source of the cold district which is the natural resource of the earth. Hence, ice can be made inexpensively and energy can be saved, so that the system can contribute significantly to the reduction of carbon dioxide gas output on the earth, and storage of objects under low-temperature, high-humidity environment can be realized.
Moreover, due particularly to the cylindrical shape of the heat-insulating outer shell, the shell has a circular cross section. Hence, in order to obtain a predetermined inner space capacity, it is possible to reduce the surface area of the wall, in comparison with one having a rectangular cross section. As a result, heat loss through the wall surface may be reduced, thereby to restrict thawing of the ice during warm season. Thus, the use amount of insulating material may be minimized, the heat insulting is two-dimensional and the volume of the ice is three-dimensional. For this reason, the larger the system, the smaller the amount of ice needed and the smaller the thickness of the heat insulating material. That is, there is achieved the effect of realization of construction cost reduction per unit storage amount.
Moreover, such circular shape has less resistance against an external force such as wind pressure against the wall surface, and the external force will be broken up into force components along the wall surface, which can be absorbed by compression stress of the material forming the wall surface. Hence, the shape is reasonable from the dynamics point of view. So that, through simplification of the building facility, the construction costs may be reduced advantageously.
According to another feature of the present invention, as exemplified by the illustrations of FIGS. 5, 7 and 11, the heat-insulating outer shell has a cylindrical shape.
According to yet another feature of the invention, in addition to the achievement of the function/effects by the invention, the heat-insulating outer shell has a circular cross section. Hence, in order to obtain a predetermined inner space capacity, it is possible to reduce the surface area of the wall, in comparison with one having a rectangular cross section. As a result, heat loss through the wall surface may be reduced, thereby to restrict thawing of the ice during warm season. Thus, the use amount of insulating material may be minimized, the heat insulting is two-dimensional and the volume of the ice is three-dimensional. For this reason, the larger the system, the smaller the amount of ice needed and the smaller the thickness of the heat insulating material. That is, there is achieved the effect of realization of construction cost reduction per unit storage amount.
Moreover, such circular shape has less resistance against an external force such as wind pressure against the wall surface, and the external force will be broken up into force components along the wall surface, which can be absorbed by compression stress of the material forming the wall surface. Hence, the shape is reasonable from the dynamics point of view. So that, through simplification of the building facility, the construction costs may be reduced advantageously.
According to yet another feature of the present invention, as exemplified by the illustrations of FIGS. 5, 7 and 11, the ice storage water tank disposing space is disposed so as to encompass the storage space.
According to yet another feature of the invention, the function/effect by the invention can be achieved. In addition, as the ice storage water tank disposing space is interposed between the storage space and the outside, the ice storage water tank disposing space not only provides cold to the storage space, but also guards the storage space, whereby the influence from the environmental change of the outside air to the storage space may be advantageously reduced. Therefore, it becomes possible to continue to provide storage for the storage objects under even better conditions for a longer period of time. Incidentally, such encompassing condition of the storage space may include various conditions such as a condition in which only a lateral side of the storage space is encompassed, a further condition in which the space is encompassed, including its lower side, and a still further condition in which the space is encompassed entirely, including all of its upper, lower and lateral sides.
According to yet another feature of the present invention, as exemplified by the illustrations of FIGS. 5, 7 and 11, the system further comprises a loading-unloading equipment capable of transporting the storage object through the entrance/exit opening.
That is, the carry-in and carry-out operations of the storage objects may be carried out speedily and efficiently. So that, the operating time period of the entrance-exit opening during the carry-in or carry-out operation of the storage object may be shortened, thereby to reduce wasteful leak of the cold air from the inside of the storage facility. And, the temperature maintenance of the storage space may be effected more easily.
According to yet another feature of the present invention, as exemplified by the illustrations of FIGS. 9 and 10, the system comprises: a heat-insulating outer shell capable of insulating inner space; an ice storage water tank capable of storing water therein disposed in an ice storage water tank disposing space provided in the inner space of the heat-insulating outer shell; a storage space for storing objects to be stored provided in the inner space of the heat-insulating outer shell; an outside-air inlet opening provided at a lower portion of the heat-insulating outer shell, the inlet opening being capable of introducing outside air into the inner space; an inside-air outlet opening provided at an upper portion of the heat-insulating outer shell, the outlet opening being capable of discharging inside air from the inner space of the heat-insulating outer shell to the outside; an object entrance-exit opening provided at an upper portion of the heat-insulating outer shell for allowing entrance-exit of the objects to and from the storage space; and a blower means W capable of being driven to selectively provide an outside air introducing state for introducing outside through the outside-air inlet opening into the ice storage water tank disposing space and an inside air circulating state for circulating the air between the ice storage water tank disposing space and the storage space.
According to another feature of the invention, when the outside air is under low temperature, by switching the blower means to the outside air introducing state, outside air is introduced through the outside-air inlet opening into the ice storage water tank disposing space, so that this air absorbs latent heat from the water stored within the ice storage water tank for freezing this water.
Thus, it has become possible to freeze the water inside the ice storage water tank by utilizing the cold source of the cold district which is the natural resource of the earth. Hence, ice can be made inexpensively and energy can be saved, so that the system can contribute significantly to the reduction of carbon dioxide gas output on the earth. And, by the cold from the ice made in the ice storage water tank disposing space, the storage space can be maintained under refrigerating condition (about 0xc2x0 C.), for allowing storage objects stored in the storage space.
Moreover, since the storage space can be maintained at a high humidity by means of saturated water vapor pressure, storage of objects under low-temperature, high-humidity environment can be realized.
Therefore, it becomes possible to provide an environment suitable for storage of agricultural products (potatoes, vegetables, fruits, live flowers, etc). Furthermore, since the storage space can be maintained at the temperature of 0xc2x0 C. approximately, the system may be used also for freezing storage of frozen articles frozen below zero.
Further, due to the relationship between the temperature and density of the air (i.e. the lower the temperature, the higher the humidity), even if the entrance-exit opening is kept open during the entry or exit of the objects into or from the storage space, in case the outside air temperature is higher than the inside air temperature of the storage space, it is possible to minimize entry of the outside air into the inner space of the heat-insulating outer shell. Hence, the maintenance of the temperature of the storage space may be effected easily.
Moreover, as the ice storage water tank disposing space is interposed between the storage space and the outside, the ice storage water tank disposing space not only provides cold to the storage space, but also guards the storage space, whereby the influence from the environmental change of the outside air to the storage space may be advantageously reduced. Accordingly, it becomes possible to continue to provide storage for the storage objects under even better conditions for a longer period of time.
On the other hand, by setting the blower means under the inside air circulating state, the cold stored in the ice storage water tank may be provided to the storage space for maintaining the refrigerating condition of this storage space.
Therefore, even in the presence of cold season or warm season, the refrigerated storage may be carried out continuously.
According to another feature of the invention, the storage facility is prepared. Then, water is charged into the ice storage water tank. When the outside air becomes sub-zero temperature, the outside-air inlet opening and the inside-air outlet opening are rendered communicable, so as to introduce the outside air into the ice storage water tank disposing space, so that the cold of this outside air may freeze the water for maintaining the ambience temperature of the storage space at a refrigerating condition. Thereafter, while the outside-air inlet opening is kept closed, the storage object is introduced through the entrance-exit opening into the storage space to be stored therein.
That is, by utilizing the natural environment, ice, whether in a small amount or in a large amount, can be made for multiple purposes, without requiring a large amount of electricity, and by using this ice the ambient temperature of the storage space may be maintained under the refrigerating condition, so that the storage objects stored in the storage space may be stored under low-temperature, high-humidity condition in a stable manner.
Further, if the amount of ice to be made is designed such that the amount is large enough not to be completely melted even when subjected to heat during the spring, summer and autumn seasons when the outside temperature is high, water and ice can coexist within the ice storage water tank throughout the spring, summer and autumn seasons. Therefore, as shown in FIG. 2, whole-year vegetables can be stored under low temperature.
And, by minimizing heat loss associated with entry and exit of the storage objects, storage of the storage objects is made possible with maintaining the refrigerating environment stable for a longer period of time.